Baseline participant characteristics and potential risk factors for SARS-CoV-2 infection
| Characteristic | No. (%) of participants* | |||
|---|---|---|---|---|
| Total n = 1062 | SickKids n = 376 | London Health Sciences n = 349 | Markham Stouffville n = 337 | |
| Age, yr, median (IQR) | 40 (32–51) | 38 (31–49) | 39 (31–52) | 42 (33–51) |
| Sex, female | 834 (78.5) | 272 (72.3) | 283 (81.1) | 279 (82.8) |
| Role | ||||
| Physician | 237 (22.3) | 121 (32.2) | 66 (18.9) | 50 (14.8) |
| Nurse practitioner | 15 (1.4) | 5 (1.3) | 3 (0.9) | 7 (2.1) |
| Nurse | 446 (42.0) | 135 (35.9) | 195 (55.9) | 116 (34.4) |
| Allied health worker | 159 (15.0) | 34 (9.0) | 47 (13.5) | 78 (23.1) |
| Respiratory therapy | 52 (4.9) | 15 (4.0) | 20 (5.7) | 17 (5.0) |
| Auxiliary health worker | 76 (7.2) | 41 (10.9) | 14 (4.0) | 21 (6.2) |
| Other† | 115 (10.8) | 39 (10.4) | 16 (4.6) | 60 (17.8) |
| Workplace | ||||
| Emergency department | 306 (28.8) | 102 (27.1) | 129 (37.0) | 75 (22.3) |
| Critical care | 245 (23.1) | 70 (18.6) | 125 (35.8) | 50 (14.8) |
| Hospital ward | 373 (35.1) | 121 (32.2) | 128 (36.7) | 124 (36.8) |
| Perioperative services or surgical ward | 157 (14.8) | 60 (16.0) | 49 (14.0) | 48 (14.2) |
| COVID-19 assessment centre | 37 (3.5) | 8 (2.1) | 5 (1.4) | 24 (7.1) |
| Other‡ | 257 (24.2) | 99 (26.3) | 51 (14.6) | 107 (31.8) |
| No. of individuals in household, median (IQR) | 3 (2–4) | 3 (2–4) | 3 (2–4) | 4 (2–4) |
| No. with ≥ 3 individuals in household (including participant) | 602/1043 (57.7) | 178/359 (49.6) | 182/349 (52.1) | 242/335 (72.2) |
| No. with children (< 18 yr) in the household | 401 (37.8) | 122 (32.4) | 121 (34.7) | 158 (46.9) |
| Underlying medical conditions | 386 (36.3) | 124 (33.0) | 135 (38.7) | 127 (37.7) |
| Race or ancestry | ||||
| Inuit, First Nations, Métis | 3 (0.3) | 0 | 1 (0.3) | 2 (0.6) |
| White | 734 (69.1) | 243 64.6 | 296 (84.8) | 195 (57.9) |
| Black | 16 (1.5) | 9 (2.4) | 3 (0.9) | 4 (1.2) |
| Hispanic | 14 (1.3) | 10 (2.7) | 3 (0.9) | 1 (0.3) |
| Asian | 172 (16.2) | 52 (13.8) | 25 (7.2) | 95 (28.2) |
| Middle Eastern | 31 (2.9) | 8 (2.1) | 12 (3.4) | 11 (3.3) |
| Other | 55 (5.2) | 21 (5.6) | 7 (2.0) | 27 (8.0) |
| Unknown/unspecified | 40 (3.8) | 33 (8.8) | 3 (0.9) | 4 (1.2) |
| Travel since Jan. 1, 2020 | 402 (37.9) | 159 (42.3) | 138 (39.5) | 105 (31.2) |
| Worked on a unit with a COVID-19 outbreak | 120 (11.3) | 3 (0.8) | 93 (26.6) | 24 (7.1) |
| Provided direct care to patient with COVID-19 | 439 (41.3) | 29 (7.7) | 230 (65.9) | 180 (53.4) |
| Known unprotected occupational exposure with direct patient care | 41/439 (9.3) | 4/29 (13.8) | 24/230 (10.4) | 13/180 (7.2) |
| Known SARS-CoV-2 positive by PCR before enrolment | 40 (3.8) | 17 (4.5) | 7 (2.0) | 16 (4.7) |
| Positivity proportion (to SARS-CoV-2 immunoglobulin G antibodies) | ||||
| Overall (at any time point) | 57/1062 (5.4) | 24/376 (6.4) | 12/349 (3.4) | 21/337 (6.2) |
| Baseline (at enrolment) | 48/1062 (4.5) | 19/376 (5.1) | 10/349 (2.9) | 19/337 (5.6) |
| 6 weeks | 53/1042 (5.1) | 22/367 (6.0) | 10/346 (2.9) | 19/329 (5.8) |
| 12 weeks | 48/966 (5.0) | 18/348 (5.2) | 11/338 (3.3) | 19/280 (6.8) |
Note: IQR = interquartile range, PCR = polymerase chain reaction, SickKids = The Hospital for Sick Children.
↵* Unless stated otherwise.
↵† Included roles such as midwife, child life specialist, research coordinator, paramedic or transport personnel, speech and language therapists, and counselors.
↵‡ Included workplaces such as diagnostic imaging, intravenous or phlebotomy, labour and delivery or midwifery, infection prevention and control, and research.